Methods, devices and a machine-readable storage medium for denoising a Computed Tomography (CT) image are provided. In one aspect, a method of denoising a CT image includes: generating an original CT image according to raw data which is obtained by scanning a subject, where a pixel count of the original CT image is greater than a preset target pixel count; obtaining a denoised image by denoising the original CT image; and obtaining a target image as a CT image of the subject by compressing the denoised image to the preset target pixel count based on an interpolation algorithm.